Telephone-transmitter.



": of New J 1 transmitters of the avoided.

Application filed October I3, 1911.

Serial No. 654,485. r

To aZZ whom it may concern- Be it known that I, HERBERT E. Snmnnvn, subject of the King of England, residing at Milburn, in the county of Essex and State ersey, have invented a V certain new and usefl Improvement in Telephone- Transmitters, of which the following a full, clear, concise, and exact description.

This invention relates to loud speaking differential type, and more particularly to the production-of a loud speaking transmitter in which the deleterious effect of using the comparatively heavy current necessary for its operation is support 10 is anfannular groovel8 defining an electrode support 19 to which is attached y soldering or Otherwise a platinum electrode 55. v

Attached to the support 10, by means of a support by the insulatingvbushings 2.1, but spaced apart therefrom by spacing bolts 22 d washers 23, is the front plate or support an annular groove 25 defining an electrode to which is attached the platinum is groove 25 is opposite the groove 18, and mounted in these two grooves is a, catli'nite bushing 27. The two electrodes, together with the catlinite bushing,

, One of the objects of this invention is to produce a. loud speaking transmitter which will operate on heavy current and in which define an electrode chamber. Formed on the usualcaslng and bell are dispensed with, the front face of the support '24- are a plu- 20 the parts being made massive and provided al y 0 m n ml heat-dissipa ing the electrode stem in flanges 28. he support 24- is provided with a hole 29 which, at its outer en is countersunk asat 30 to front plate or support 24 by screws 33. The rear face of the face plate 31 is recessed to form a support for an insulating washer 34 against which abuts a diaphragm 35.

Mounted on the front face of 4 is a spring member 38 fastened to the support by the screws 37. The outer end oft-his spring 36 contacts with the washer 4301; the diaphragm 35, damping spring for for the free expansion of the movable elecrode in the direction of its diameter and of the direction of its Another'object is the provision of a gland of peculiar design through which the electrode stem passes, whereby the use of textile a ics is obviated and satisfactory mechani djustment provided.

Another object of this. invention is the use of catlini-te in the construction of the walls of the electrode chamber;

In the drawintgsFigure l is spective view 0 the improved partly in section;

the diaphragm.

Mounted in the electrode chamber is a movable or plunger electrode 38.; This electrode 38'is rovided with a stem through the hole 30'in'the support 24 and through a perforation in the diaphragm 35. The outer end of this stem is threaded'as at i and provided with a thuinbnut 40. Mounted on" t stem is an insulating bushiing- 41 0f catlinite. A mica washer 42 is mounted in the'stufiing I l .')etween this washer 42 and the insulating I" Washer 435'. mounted on the rear face of the diaphragm, is a spring 44 which maintains the Washers 42 and 43 in place. permitsthe diaphragm to vibrate in response to the voice currents and compensates for change a detail per transmitter, Fig. 2 is a sectional ele a diagram of i There is shown a transmitter having a massivelmck plate or support 10' with af rearwardly extending portion 11 on which are formed flanges 12 for thepurpose of dissipating heat. Attached to the rearward end of the part 11 is a lug 13 for attachment to the standard 14 of the ordinary desk stand. Mounted on the fr nt of the sup port 10 is a heat-dissipating plate 15, attached to the su port 10 by means of screws- 16 and separateftherefrom by a plurality of plurality of screws 20,,insulated from the.

the support passing box 30, and located I this support 24- is 4 means of the l 9o insulating and con- 2h thereto,

in distance between the diaphragm and the electrode 38. The electrode chamber is partly filled with carbon granules 45.

The structure of the granular chamber, described above, is one that permits the equalization of gas pr'essureof the two sides of the movable electrode 38, owing to the movable electrode being of smaller diameter than the inside diameter of the catlinite bushing 27. The catlinite bushing 27 fitting loosely in the annular grooves on and back plates allows any excess of gas to escape from the chamber without at the same time permitting the escape of carbon granules. The movable electrode 38 has sufiicient room within the catlinite bushing 38 to allow it to expand in the direction of its diameter, and the stem 39 attached thereto may expand in the direction of its length, any increase in length due to heating'being compensated for by means of the spring 44.

Mounted on the rear face of the support 10 is a plate 46 formed of insulatingmaterial. A conducting block 47 is fastened and a conductor 48 leads therefrom and makes contact with the diaphragm and thus with the movable electrode 38, as clearly shown in Fig. 1. Insulating bushings 50 are provided to insulate the conductor 48 from the back support 10 and the front support 24. A binding post 51 is mounted on the plate 46 and makes contact I with the front plate 24: at 52. This binding post 51 passes through a hole 53 in the back plate 10, and is insulated therefrom by the insulating washer 5i.

, In Fig. 3, which shows a diagram of the circuits, the electrodes 55 and 56 are connected to the extremities of the primary 60 nected to the line.

of the induction coil 61, by the wires 7 O and 71, respectively, the secondary 62'bei'ng con- The movable electrode 38 is connected to the middle point of the primary 60 through The operation is as follows t-The normal current flow is in opposite directions through the primary, the core remaining neutral. One oscillation of the diaphragm 35 and its associated electrode 38 causes current to rise in one half of the primary 60 and simultaneously to fall in the other half, and, asthese eifects are opposite the resultant action on the secondary produces a strong rise in one direction through the Whole length .of the secondary equal to the sum of the individual effects. On the reverse oscillation the current in the secondany first falls to Zero and then'reverses to an equal degree. L

The construction herein shown is such that a transmitter of this type will operate efiiciently under comparatively heavy current without undue tion is open, no casing being provided.

metal parts are made heavy and provided the front 1 the local battery 63.

heating. The construewith ample means for dissipating any heat that may be generated. The use of catlinite as insulation, and as the material for the walls of the granule chamber insures durability of the transmitter, under the severest service conditions.

I claim:

1. In a telephone transmitter, the combination of two stationary electrodes spaced apart, heat-dissipating projections integral therewith, an insulating bushing located between and concentrically mounted with respect thereto and defining a chamber, carbon granules therein, a plungerv electrode of less diameter than the inside diameter of the bushing, mounted in said chamber, whereby the plunger electrode may have room to expand in the'direction of its diameter, a stufling box in one of the stationary electrodes,-a diaphragm; a stem integral with the plunger electrode, passing through the shifting box and adjustably connected with the diaphragm, a mica ,washer mounted in the stufiing box and surrounding the electrode stem, and a spring mounted between the diaphragm and the micawasher. whereby the washer is held in the stuffing box and the escape of carbon granules from the chamber is prevented.

2. In a telephone transmitter, the combination of two stationary electrode supports spaced apart. heat-dissipating flanges integral therewith, electrodes mounted on adj acent faces thereof, an annular catlinite bushing located between the electrode supports and forming therewith an electrode chamher, a movable electrode 'mounted in said chamber, a diaphragm, and means mechanically connecting said diaphragm with said said connecting means movable electrode,

in one of the stapassing through an orifice "tionary electrode supports, and granular carbon in said chamber and on either side of said movable electrode.

3. In a telephone transmitter, the combination-of a rigid electrode forming the back of the carbon chamber, trode spaced therefrom and forming the front wall-of the carbon chamber, two an-. nular grooves, one in each electrode, and a bushing fitting 4. In a telephonejtransmitter, the comh1-' into said annular grooves.

a perforated elecnation of massive front and back plates spaced apart and provided with heat-dissipating flanges, annular grooves in the opposing faces of said*back plates defining electrode supports, electrodes mounted thereon, a heat-resisting bushing loosely mounted in said annular grooves and form'- ing with said back plates an electrode chamber, a movable elect-rode mounted in said chamber out of contact with either wall thereof, a diaphragm; connecting means passing through an orifice in one of said back plates and connecting said movable electrode and said diaphragm together, whereby the vibrations of. said'diaphragm are communicated to said electrode, granular carbon in said chamber on either side of said movable electrode, and means to prevent the escape of the carbon granules through the orifice in the front plate.

5. In a telephone transmitter, the combination of two rigid electrodes, massive supports therefor spaced apart and provided with heat-dissipatingprojections, a catlinite bushing located between said supports. and forming therewith an electrode chamber, a diaphragm, a movable electrode located in said chamber and of less diameter than the inside diameter of the bushing, means for connecting said electrode and diaphragm together, said meanscomprising a stem rigidly attached to the electrode and passing through one of the supports and through the diaphragm, resilient compensating means located between the diaphragm and one of the supports, and means on the end of the stem whereby the distance between the diaphragm and the movable electrode may be adjusted.

6. In a'telephone transmitter, the combination with a stationary back plate, an electrode mounted on the front face thereof, an annular groove in said back plate and surrounding the electrode, ieat-dissipating flanges formed on the rear faceof the back piate, a stationary front plate spaced apart from but connected to the back plate, heatdissipating flanges formed on the front face t-rode in said chamber, a diaphragm, a stem mechanically connecting the diaphragm and 'theinovable electrode, said stem passing through a perforatio in the stationary front plate, a glaid in the frontface of the front plate, and a mica washer in said gland and surrounding" said stem, thereby preventing the escape of "carbon anules from said chamber while. permittmg the escape of gas.

7. In a telephone transmitter, the combination of a diaphragm having a central perforation, two rigid electrodes, one having a central perforation, a movable electrode between said rigid electrodes, ble stem passing through the in said diaphragm and said per rated rigid electrode, one end operatlvely connected with the diaphragm, the other end attached to the movable electrode, and means for compensating for the expansion of said stem. I

In witness whereof, I, hereunto subscribe my name this 12th day of October A. 1)., 1 ll.

HERBERT E. snannvn. Witnesses F. P. MoIiIrosH, F. TOOHEY.

an expanse fperforations Gopies an this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

"40" chamber, a movable elec- 

